The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefor.
(1) Field of the Invention
The present invention relates generally to deployment of acoustic arrays underwater, and more particularly to an acoustic array and deployment system and method for deploying an acoustic array from a moving underwater vehicle such as a supercavitating torpedo.
(2) Description of the Prior Art
Unmanned underwater vehicles typically have acoustic array sensing systems mounted in their nose structures. However, the nature of some underwater vehicles precludes the use of such sensing arrangements. For example, a supercavitating torpedo generates a cavitation bubble about the torpedo. The noise generated by the cavitation bubble severely reduces the effectiveness of any acoustic array mounted anywhere on the supercavitating torpedo. Thus, acoustic sensing for a supercavitating torpedo must be accomplished outside of the torpedo""s cavitation bubble.
One approach for getting an acoustic array away from a vehicle is to tow it behind the vehicle. In the case of the supercavitating torpedo, this does get the acoustic array physically away from the cavitation bubble. However, since the towed array will be in line with the torpedo and its intended target (that is aligned with the torpedo""s direction of travel), the cavitation bubble surrounding the torpedo will tend to mask the target in the acoustic array""s endfire beam.
Accordingly, it is an object of the present invention to provide a method and system for deploying an acoustic array from an underwater vehicle.
Another object of the present invention is to provide a method and system for deploying an acoustic array from a supercavitating underwater vehicle to minimize the effect of the cavitation bubble surrounding the underwater vehicle on the acoustic array.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, an acoustic array deployment system for an underwater vehicle is provided along with a method for carrying out such deployment. A weighted projectile is housed onboard the underwater vehicle. An optical fiber based acoustic array has a first end thereof coupled to the weighted projectile and has a second end thereof coupled to the underwater vehicle. Means are provided for maintaining the acoustic array in a spooled configuration while the weighted projectile is housed onboard the underwater vehicle. Means are also provided for launching the weighted projectile from onboard the underwater vehicle in a gravitationally downward direction that is not aligned with the underwater vehicle""s direction of travel. As a result, the acoustic array is paid out from its spooled configuration as the weighted projectile is launched and then sinks under its own weight. By establishing the line array""s broadside beam in a direction that is away from the vehicle and approximately perpendicular to the vehicle""s direction of travel, the relative angular difference between the underwater vehicle and target can be used to guide the vehicle towards the target.